Can we use minimally invasive mitral valve surgery as a safe alternative to sternotomy in high-risk patients?

Outcomes of minimally invasive versus conventional sternotomy for redo mitral valve surgery according to Mitral Valve Academic Research Consortium: A systematic review and meta-analysis

A minimally invasive approach through right mini-thoracotomy for redo mitral valve surgery may improve patients' outcomes compared to median sternotomy. This study aims to evaluate the outcomes of both procedures according to the Mitral Valve Academic Research Consortium (MVARC). This systematic review and meta-analysis were performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Literature searching was performed in several databases including PubMed, EBSCOhost, Scopus, and Proquest up to 28 February 2022. Meta-analysis using proportions or means was applied. A total of 13 retrospective cohort articles were included in this study. The incidence of in-hospital mortality (3% vs 9.2%, OR = 0.35; 95% CI: 0.21-0.58; P ≤ 0.0001), reintervention for bleeding (3.8% vs 5.9%, OR = 0.56; 95% CI: 0.32-0.97; P = 0.04), and acute renal failure (5% vs 12%, OR = 0.29; 95% CI: 0.23-0.65; P = 0.0003) was significantly lower in mini-thoracotomy (MINI) group compared to median sternotomy (STER) group. The incidence of neurologic events (3.4% vs 5.5%, OR = 0.66; 95% CI: 0.4-1.08; P = 0.1) and arrhythmia (19.5% vs 25.5%, OR = 0.64; 95% CI: 0.38-1.09; P = 0.1) were also lower in MINI group compared to STER group but was not significant statistically. No significant differences were found in myocardial infarct (1% vs 1%, OR = 0.71; 95% CI: 0.06-8.85; P = 0.79) between MINI and STER group. A minimally invasive surgery through right mini-thoracotomy is associated with a lower incidence of in-hospital mortality, reintervention for bleeding, and acute renal failure. It is a safe alternative to median sternotomy for redo mitral valve surgery.

Sex-specific differences and postoperative outcomes of minimally invasive and sternotomy valve surgery

OBJECTIVES

Female sex is an established risk factor for postoperative complications after heart surgery, but the influence of sex on outcomes after minimally invasive cardiac surgery (MICS) for valvular replacement/repair remains controversial. We examined whether the role of sex as a risk factor varies by surgical approach [MICS vs conventional sternotomy (ST)] and further assessed outcomes among female patients including in-hospital mortality and postoperative complications by surgical approach.

METHODS

We analysed data from a multicentre registry for patients who underwent isolated aortic valve and mitral surgery with MICS or ST. The primary outcome was in-hospital mortality. Propensity score matching was used to minimize between-group differences.

RESULTS

Among the 15 155 patients included in the study, 7674 underwent MICS (50.6%). Female sex was equally distributed in the MICS and ST groups (47.3% vs 47.6%, respectively). Risk for surgery was higher in the ST group than in the MICS group {EuroSCORE II: 4.0 [standard deviation (SD): 6.8] vs 3.7 [SD: 6.4]; P = 0.005}, including among female patients only [ST vs MICS 4.6 (SD: 6.9) vs 4.2 (SD: 6.3); P = 0.04]. Mortality did not significantly vary by procedure among women [MICS vs ST, 2.4% vs 2.8%; hazard ratio 1.09, 95% confidence interval 0.71-1.73; P (surgical approach × sex) = 0.51]. The results also did not vary after adjusting for confounders.

CONCLUSIONS

Female sex was associated with higher mortality in patients undergoing valve surgery, regardless of surgical approach. In female patients, MICS did not provide any benefits over ST in terms of in-hospital deaths or postoperative complications.

SUBJECT COLLECTION

117, 125.

Minimally invasive mitral valve surgery

There is considerable interest and demand in the application of minimally invasive techniques in cardiac surgery driven by multiple factors including patient cosmesis and satisfaction, reduction of surgical trauma and the development of specialized instrumentation that allows these procedures to be performed safely. Minimally invasive mitral valve surgery (MIMVS) has been conducted for more than 25 years and has been shown to offer multiple benefits including better cosmetic results, enhanced post-operative recovery, improved patient satisfaction and most importantly, equivalent clinical outcomes with regards to quality and safety when compared to the standard sternotomy approach. MIMVS may be particularly beneficial in certain subgroups of patients, for example patients undergoing redo mitral valve surgery. In this article, we discuss patient selection criteria for MIMVS, the merits and drawbacks of MIMVS relative to conventional sternotomy approaches, and detail procedural aspects including anaesthetic management, intraoperative technique, and important considerations in myocardial protection and cardiopulmonary bypass (CPB). When considering developing a MIMVS programme, as for any new technique, a team approach to the introduction of the programme is essential. Although it is clear that patient selection is important, particularly early in a surgical programme, with experience complex repairs can be performed through a minimally invasive approach with excellent outcomes.

Is tri-port totally thoracoscopic surgery for mitral valve replacement a feasible approach?

Background

Minimally invasive cardiac surgery is an attractive approach for both surgeons and patients. This study aims to describe the experience of mitral valve replacement (MVR) with Ma's tri-port totally thoracoscopic cardiac surgery technique (MTCST) and to prove the feasibility and safety of this technique.

Methods

A total of 490 consecutive patients undergoing MVR were divided into MTCST group (MT group, n=267) and conventional median sternotomy group (MS group, n=223). The perioperative characteristics and the follow-up information were recorded and analyzed between the two groups.

Results

The in-hospital mortality and re-operation rate were not significant between the two groups. Compared with the MS group, cardiopulmonary bypass time and aortic cross-clamp time were both longer in the MT group while total operative time was similar to the MS group. Patients in the MT group had less pain and required a decreased analgesic administration than that in the MS group. Intraoperative blood loss, perioperative blood transfusion and the postoperative drainage were all significantly reduced in the MT group as compared to the MS group. Mechanical ventilation time, ICU duration, hospitalization time and hospitalization cost were decreased in the MT group. Patients undergoing MVR with MTCST had a higher Medical Treatment Satisfactory Score than those with conventional sternotomy.

Conclusions

MTCST for mitral valve disease was technically safe and feasible. The results showed that MTCST was a suitable minimally invasive alternative to the conventional sternotomy approach and was a desirable approach for patients with mitral valve disease.

Minimally invasive and transcatheter approaches for mitral valve surgery

Mitral valve surgery has evolved through the ages, in response to prevalent epidemiology of mitral pathologies. In the modern era, advances in technology has allowed physicians to help a wider spectrum on increasingly sicker patients. This review summarises these advances and its associated evidence base for safety and efficacy.

Intraoperative Implantation of Temporary Endocardial Pacing Catheter During Thoracoscopic Redo Tricuspid Surgery

BACKGROUND

The placement of a temporary epicardial pacing wire is a challenge during a minimally invasive redo cardiac operation. The aim of this study is to assess the application of temporary endocardial pacing in patients who underwent minimally invasive redo tricuspid surgery.

METHODS

Perioperative data of consecutive patients who underwent thoracoscopic redo tricuspid surgery were collected. All the tricuspid surgeries and combined procedures were performed under peripheral cardiopulmonary bypass without aortic cross-clamping. A sheath was introduced into the right jugular vein beside the percutaneous superior vena cava cannula and a temporary endocardial pacing catheter was guided into the right ventricle via the sheath prior to the right atrial closure. The pacemaker was connected and run as needed during or after operation.

RESULTS

A total of 33 patients who underwent thoracoscopic redo tricuspid surgery were enrolled. Symptomatic tricuspid valve regurgitation (93.9%) and tricuspid valvular prosthesis obstruction (6.1%) after previous cardiac operations were noted as indications for a redo surgery. The mean time from previous cardiac operation to this time redo surgery was 13.3±6.4years. Isolated tricuspid valve replacement was performed in 18 patients (54.5%) and tricuspid valve plasty combined with or without mitral valve replacement was performed in 15 patients (45.5%). A temporary endocardial pacing catheter was successfully placed in the right ventricle for all patients with good sensing and pacing. No temporary pacing related complications occurred from insertion to removal of pacing catheter in the patients.

CONCLUSIONS

This application of temporary endocardial pacing provided a safe and effective substitute for epicardial pacing in patients who underwent minimally invasive redo tricuspid surgery.

A Simplified Technique for Correcting Mitral Valve Regurgitation Via Minimally Invasive Approach

Mitral valve regurgitation may require complex repair techniques that are challenging in minimally invasive and may expose patients to prolonged cardiopulmonary bypass and cross-clamp times. Here, we present a stepwise operative approach that may facilitate the repair of the mitral valve in a minimally invasive fashion and may be carried out even when multiple posterior segments are involved. This how-to-do article presents a method that was performed in 148 patients that were referred to our institution for severe organic mitral regurgitation between 2008 and 2016. At mean ± SD follow-up of 45.5 ± 27 months, freedom from recurrent of mitral regurgitation 2+ or greater and reoperation was 95.2%.

Early and long-term results of minimally invasive mitral valve surgery through a right mini-thoracotomy approach: a retrospective propensity-score matched analysis

Background

Minimally invasive mitral valve surgery (MVS) via right mini-thoracotomy has recently attracted a lot of attention. Minimally invasive MVS shows postoperative results that are comparable to those of conventional MVS through the median sternotomy as per various earlier studies.

Methods

Between 2000 and 2016, a total of 669 isolated mitral valve procedures for isolated mitral valve regurgitation were performed. A propensity score-matched analysis was generated for the elimination of the differences in relevant preoperative risk factors between the cohorts and included 227 patient pairs. Only degenerative mitral valve regurgitation was included. The aim of our study was to examine if the minimally MVS is superior to the conventional approach through sternotomy based on a retrospective propensity-matched analysis. The primary endpoints were early mortality and long-term survival. The secondary endpoints included postoperative complications.

Results

The in-hospital mortality rate was significantly higher within the conventional sternotomy cohort (3.1%, n = 7 vs 0.4%, n = 1 for the minimally invasive cohort; p = 0.032). The incidence of stroke and exploration for bleeding was comparable. In contrast, the necessity for dialysis was significantly lower in the minimally invasive cohort (p = 0.044). Postoperative pain was not significantly lower in the minimally invasive MVS cohort (p = 0.862). While patients who underwent minimally invasive MVS experienced longer bypass and cross-clamp times, their lengths of stay in the intensive care unit and in the hospital, did not differ from the conventionally operated collective (p = 0.779 and p = 0.516), respectively. The mitral valve repair rate of 81.1% in the minimally invasive cohort was significantly superior to that of the conventional approach, which was 46.3% (p < 0.0001). The one-, five-, and 10-year survival rates were significantly higher in the minimally invasive cohort compared to the conventional approach (96%, 90%, and 84% vs. 89%, 85%, and 70%; log rank p = 0.004).

Conclusion

Despite prolonged cardiopulmonary bypass and cross-clamping times, the minimally invasive MVS may be considered a safe approach that is equivalent to standard median sternotomy with lower early mortality and superior long-term survival.

Risk factors to predict leg ischemia in patients undergoing single femoral artery cannulation in minimally invasive cardiac surgery

BACKGROUND

In peripheral cannulation for cardiopulmonary bypass, there is always a risk of ischemia in the extremities, caused by femoral artery cannulation. This report aimed to evaluate the outcome and the risk factors in patients undergoing minimally invasive cardiac surgery in mitral valve surgery.

METHODS

We retrospectively reviewed all minimally invasive mitral valve surgery at our institute from May 2014 to December 2016. Operative outcomes and intra-operative monitoring for distal leg saturation were measured by the near-infrared spectroscopy values. For post-operative outcomes, the creatinine phosphorus kinase level was measured for the assessment of leg ischemia. Risk factors were evaluated for the elevation of post-operative creatinine phosphorus kinase.

RESULTS

There were 162 patients who underwent single femoral artery cannulation for minimally invasive mitral valve surgery. The mean operation, cardiopulmonary bypass and aortic cross-clamp time were 212±44, 124±30, 76.6±22 minutes (min), respectively. The factors related to increased creatinine phosphorus kinase were male, body mass index, larger cannula size, operation time, cardiopulmonary bypass time and aortic cross-clamp time. The measurement of minimum near-infrared spectroscopy values did not show any association with creatinine phosphorus kinase elevation. There were significant associations between body mass index, cannula size and operation time and post-operative creatinine phosphorus kinase increase by multiple regression analysis. Two male patients had extremely high post-operative creatinine phosphorus kinase (18188 U/L and 16831 U/L) and they had high body mass index, large cannula size and longer operation time.

CONCLUSIONS

In peripheral cannulation for minimally invasive cardiac surgery, body mass index, cannula size and operation time can be considered as risk factors for leg ischemia.

Cardiopulmonary bypass does not induce lung dysfunction after pulmonary thrombarterectomy: role of pulmonary compliance

OBJECTIVES

Pulmonary endarterectomy is a heavy surgical procedure that is performed under cardiopulmonary bypass (CPB) and aimed to cure postembolic pulmonary hypertension. Reperfusion oedema is both the hallmark of successful surgical procedure and the most frequent postoperative complication. Post-CPB lung dysfunction was not mentioned in any report. We undertook a study to determine whether post-CPB lung dysfunction was present in these patients.

METHODS

In a retrospective cohort study with matching on some baseline covariates, we selected 41 patients who had undergone pulmonary endarterectomy and in whom pre-, intra- and postoperative records were complete. The control group was composed of 39 patients operated on from elective cardiac surgery during the same period and matched with a study group for age, gender, body mass index, blood creatinine, diabetes and baseline partial pressure of oxygen/fraction of inspired oxygen ratio. Criteria for post-CPB lung dysfunction were partial pressure of oxygen/fraction of inspired oxygen ratio decrease and bilateral basal oedema. Explanatory variables for post-CPB lung dysfunction were coronary arterial bypass, pleura opening, static pulmonary compliance measured at the time of thorax closed then retracted, fluid infusion, transfusion and vasopressors.

RESULTS

All patients operated on from pulmonary endarterectomy presented radiological oedema reperfusion in surgical unblocking areas. Among them, only 2 had bilateral basal oedema when compared to the 24 patients from the control group (P < 0.001). Partial pressure of oxygen/fraction of inspired oxygen ratio increased in the study group and decreased in the control group (30 ± 109 vs -67 ± 134 mmHg, P < 0.001). Control group patients with high-baseline pulmonary compliance were at risk for post-CPB lung dysfunction.

CONCLUSIONS

Patients operated on from pulmonary endarterectomy were saved from post-CPB lung dysfunction. The latter could be induced by a mechanical phenomenon.

Contemporary outcomes in reoperative mitral valve surgery

Objective

Data suggest that redo mitral valve surgery is being performed in increasing numbers, possibly with superior results according to single-centre studies. The purpose of this study is to describe outcomes of redo mitral valve surgery and identify risk-adjusted predictors of poor outcomes.

Methods

All (11 973) open mitral valve cases were evaluated (2002–2016) from a regional Society of Thoracic Surgery (STS) database. Patients were stratified by primary versus redo mitral valve surgery. Mixed effects logistic regression models including hospital as a random effect were used to identify risk factors for patients undergoing redo mitral valve surgery.

Results

Of all mitral valve cases, 1096 (9.7%) had a previous mitral operation. Redo patients had higher rates of valve replacement and preoperative comorbidities resulting in more complications, operative mortalities (11.1%vs6.5%, p<0.0001) and higher resource utilisation. Several factors independently increased risk for composite STS major morbidity and 30-day mortality, including cardiogenic shock (OR 10.3, p=0.0001), severe tricuspid insufficiency (OR 2.3, p=0.001), urgent/emergent status (OR 1.8, p=0.001) and concurrent coronary artery bypass grafting (OR 2.4, p=0.002). The volume of redo mitral valve surgery increased 10% per year and the observed-to-expected ratios (O/E) for operative mortality in redo mitral surgery improved from 1.44 early in the study period to 0.72 in the most recent era.

Conclusions

Redo mitral valve surgery accounts for approximately 10% of mitral valve operations and is associated with increased risk and resource utilisation. However, as the volume of redo mitral surgery increases, outcomes have dramatically improved and are now better than predicted.

Early pulmonary compliance increase during cardiac surgery predicted post-operative lung dysfunction

Introduction:

Lung dysfunction following cardiac surgery is currently viewed as the consequence of atelectasis and lung injury. While the mechanism of atelectasis has been largely detailed, the pathogenesis of lung injury after cardiopulmonary bypass is still unclear. Based upon clinical and experimental studies, we hypothesized that lungs could be injured through a mechanical phenomenon.

Methods:

We recorded pulmonary compliance at six key moments of a heart operation in 62 adult patients undergoing elective cardiac surgery. We focused on the period lasting from anesthetic induction to aorta unclamping. We calculated the variation of static and dynamic pulmonary compliance caused by thorax opening; ΔCstat1 and ΔCdyn1 and that caused by cardiopulmonary bypass, ΔCstat2 and ΔCdyn2. Blood gases were performed under standardized ventilation after anesthetic induction and after surgical closure. The PaO2/FiO2 ratio was calculated. ∆PaO2/FiO2 was the criterion for lung dysfunction. We compared ΔCstat1 and ΔCdyn1 with both ∆PaO2/FiO2 and, respectively, ΔCstat2 and ΔCdyn2.

Results:

Static and dynamic compliance increased with the opening of the thorax and decreased with the start of cardiopulmonary bypass. The PaO2/FiO2 ratio diminished after surgery. ΔCstat1 and ΔCdyn1 were negatively correlated with both ∆PaO2/FiO2 (r=-0.42; p<0.001 and r=-0.44; p<0.001) and, respectively, with ΔCstat2 and ΔCdyn2 (r=-0.59; p<0.001 and r=-0.53; p<0.001).

Conclusions:

Increased pulmonary compliance induced by the opening of the thorax is correlated with worsened intrapulmonary shunt after cardiopulmonary bypass. A mechanical phenomenon could be partly responsible for post-operative hypoxemia.

Minimally invasive aortic valve surgery

Aortic valve disease is a prevalent disorder that affects approximately 2% of the general adult population. Surgical aortic valve replacement is the gold standard treatment for symptomatic patients. This treatment has demonstrably proven to be both safe and effective. Over the last few decades, in an attempt to reduce surgical trauma, different minimally invasive approaches for aortic valve replacement have been developed and are now being increasingly utilized. A narrative review of the literature was carried out to describe the surgical techniques for minimally invasive aortic valve surgery and report the results from different experienced centers. Minimally invasive aortic valve replacement is associated with low perioperative morbidity, mortality and a low conversion rate to full sternotomy. Long-term survival appears to be at least comparable to that reported for conventional full sternotomy. Minimally invasive aortic valve surgery, either with a partial upper sternotomy or a right anterior minithoracotomy provides early- and long-term benefits. Given these benefits, it may be considered the standard of care for isolated aortic valve disease.